Publication Type
Journal
Journal Name
Nano Letters
Publication Date
Page Numbers
3720 to 3725
Volume
9
Issue
11
Abstract
The polarization screening mechanism and ferroelectric phase stability of ultrathin BaTiO3 films exposed to water molecules is determined by first principles theory and in situ experiment. Surface crystallography data from electron diffraction combined with density functional theory calculations demonstrate that small water vapor exposures do not affect surface structure or polarization. Large exposures result in surface hydroxylation and rippling, and in reversal of the polarization accompanied with formation of surface oxygen vacancies. Understanding interplay between ferroelectric phase stability, screening, and atomistic processes at surfaces is key to control of low-dimensional ferroelectricity.
